Electromagnetic relay



Filed Dec. 5, 1942 nventor;

HOLZ/,4M A'. ADAY,

` Gttorneg Patented Aug. 7, 1945 UNITED? lSTATES PATE-NT OFFICE 2,381,080 ELnc'rnoMAGNn'nc RELAY william A. Ray. Los Angeles, cam; Application December s. 1942, serial No. 467.965

` (ci. 11H36) 3 Claims.

My present invention relates to electromag netic relays, of the low energy-consumption type. for operating condition controlling means such as electrical contacts or pilot-valve jets.

In my copending application, Serial No. 456,358, died August 27, 1942, now'Patent No. 2,358,828, granted September 26, 1944, of which the present application is a continuation in part, I havedis closed an electromagnetic operator, of the series working-gap type. the energy vconsun'iption oi which is very small in comparison with that ci conventional electromagnetic operators capable of performing equivalent work; the improvement residing mainly in the provision of a core ha ing, at its ends, enlargements forming pole faces which are considerably greater in area than the cross-sectional area of the body of the core. The improved operation of that device is mainly due to the fact that, when the iiux density in the core (produced by a weak magnetizing force) is at a point considerably below the knee of the magnetization curve for the core material, the flux densi-ty in the large-area pole face is substantially the same as that which could be produced by the weak magnetizing force if the crosssectional area of the body of the core were not reduced; reduction of the body area making possible the use of a coil winding of small mean turn diameter and correspondingly small electrical resistance. It is a general object of the present invention to apply similar principles to provide a low energy-consumption electromagnetic relay.

More epeeihcally, 1t is an object ci this inventienv te provide an electromagnetic relay come prising a imshaped core having, at the endso its side arms,-means.deflning pole faces, the areas of which are considerably greater than the crosssectional area, of the main body portion o! the core Anotherobject is the provision, in an electro-v magnetic relay of the character described, of a bracket for mounting the condition controlling means operated bythe relay; which bracket isV supported by the enlarged pole-face-denning means. j I I Another object is tofreduce the actual length of an elongated U-shaped core without reducing Figure l is a side elevation of an electromagnetic relay embodying my invention;

Figure 2 is an end elevation, as viewed from lthe left, o' the reiay shown in Figure 1;

Figure Si is an'enlarged fragmentary view, in perspective, showing conetructional details of the relay; and

Figure i is n view, in perspective, of a. modied .form of core for the relay.

he is best seen in s, the end portions i6 of each strip are bent hacirtvardly parallel to the middle portion it in spaced relation thereto, and their extremities are retient outwardly at rightangies to the middle portions to form arms le, the middle portions of `which arms are curved to conform to the cylindrical surface 'of the core electromagnet.

, be increased when the materigl arm, to which they are clamped at their sides by screws it. in the process oi' formation o heads it and is?, the strips are inserted through slots 2t punched in a bracket il, of non-magnetic materiali such es brass., so that when the heads are formed and clamped to the core arms the bracket is rigidly supported thereby.

The outer surfaces ai! and 23 of the heads I6 and i5. respectively, define the'pole faces of the in the particular construction shown, the area oi each pole face is approximately ten times that or the cross-sectional area oi.' its respective'core arm, as is clearly seen in Fig. 2. The ratio of the area of the pole face to the cross-sectionalarea of the body of the core (the portion on which the coil is woundl may of the'core and head is of high permeability and the flux density is very low-such as can be produced by anA ordinary pilot-bumer-heated ytherinoelectric generating device. When the flux density is higher, het

its effective length, this object being achieved by forming the core as a continuous double-U.

Other objects and advantages of theA invention will be found in the description, the drawing, and in the claims: and for full understanding of the invention reference may be had to the following detailed description and accompanyingl drawing, wherein:

still considerably below the knee of the magnetization ,curve for the core material. better results may be produced by somewhat decreasing the area ratio.

Fulcrumed on 4the pole face of the upper core head i4 toward the top end of the same is an armature 2i, the armature being formed to provide a transverse knife-edge 25 which bears in a notch 28 cut in the surface of the core head; lateral movement of the armature being prevented by portions 21 struck up from the edgw 5 oi' the bracket 2i. Carried by the bent lower end portion of the armature is a contact 2l which is engageable with a relatively. ilxed contact 2l, insulatingly mounted on the bracket Il, when the amature is attracted-towardthe pole face 2l upon passage of current through the coil windings l! and I3. Biasing the armature away from the pole faces is a spring lil compressed between the amature and a turned-over upper` end portion 3| of bracket 2l; and limiting move'- ment of the amature in itsbiased direction is a stop-screw l2 threaded in a turned-over lower end portion 33 ci the bracket. For electrically connecting the contacts of the relay in a circuit. the armature is provided with a exible pig-tail 3|, and the screw portion oi the ilxed contact 29 is threaded in the insulated eyelet of a ter minal lug 35.

While the general construction shown in Figs.

1-3 is that preferred, it is not essential that the pole face on which the armature is pivoted be enlarged, especially il the armature is maintained in good flux-transfer relation to that end oi the core as by a resilient strip oi magnetic material joining it permanently to the core; however, in y the construction shown, both of the pole faces are effective in the attraction ci the armaturethe width of the armature being the same as `that of the pole faces so that the free portions of the armature adjacent the pole faces are coextensive therewith and hence relatively large. While the armature is shown fuicrumed directly on the pole face, in some cases it may be separated therefrom by a minute air-gap (provided by nonmagnetic material) in order to prevent mag-- netic sticking; such separation-being desirable when the area of the bearing surface of the armature is relatively large.

In Fig. 4 is shown a modified form of core for the relay. This core consists of a pair of U- shaped members Il and 3l joined together at one of their respective ends by a strap 3l to form a double-U; all these parts, of course, being of magnetic material. It will be apparent that the core is electively an elongated U re-bent in the middle to provide fourl side arms for the coil winding 3i. Without increasing its actual length, the eective length of the core is thus greatly increased so that the coil winding may be com-v posed of many turns of small mean diameter,

respective side arm of the core;

whereby its electrical resistance is considerably reduced. When this core is employed in the construction of a relay of the type shown in the other figures, it is provided with heads similar to those indicated at i4 and l5 in Fig. 1.

While I have herein shown and described specific embodiments of my invention, I wish it to be understood that modifications may be made without departing from the spirit ci the invention, and that I intend therefore to be limited 'only by the scope of the appended claims.

li claim as my invention:

1. In an electromagnetic operator: a U-shaped core; an energizing coil winding for said core; means, of magnetic sheet material, at the free end of each of the side arms of said core and defining a pair of spacedmpart and substantially coplanar pole faces; each or said pole-face-delining means being formed to provide a hat first portion, one surface of which defines said pole face, a second portion parallel to and spaced from said first portion, and an end portion at rightan'gles to the other portions and attached to the a generallyrectangular bracket of non-magnetic material re ceived between the spaced-apart first and second portions of both of said pole-face-de'flning means and rigidly supported thereby; and an armature cooperable with said core and mounted by the aid of said bracket.

2. In an electromagnetic operator: a U-shaped core, an energizing coil winding for said core, means of magnetic material at the free end of each of the side arms of the .core and deilning a pair of enlarged and substantially coplanar pole faces, a bracket of non-magnetic material, each of said pole-face-deflning means being formed to receive within it and tightly hold a portion of said bracket, and an armature cooperable with said core an'd mounted by the aid of said bracket.

3. An electromagnet comprising an elongated U-shaped core the free ends of which form a pair of pole faces, said core being rebent in a U-shape to form a double-U having four side arms; and a coil winding around each of said side arms for so energizing the core that said pole faces are at opposite polarities.

WILLIAM A. RAY. 

